textproduct: Quad Cities

KEY MESSAGES

- More accumulating snow late tonight through much of the day on Saturday. Similar system to this most recent one, but with colder temperatures making for efficient accumulation. NBM has 60-80% probabilities of 2-4" amounts much of the area near/south of I-80 where Winter Weather Advisories have been posted. Locally higher amounts are possible, but uncertainty in the location of this higher band potential.

- Very cold/arctic air moving in for the weekend. Biting wind chills well below zero late tonight, and especially Saturday night into Sunday morning where wind chills of -20 to -30 are likely to necessitate headlines.

- Warming trend is expected next week.

SHORT TERM /THROUGH SATURDAY/

Issued at 337 AM CST Fri Dec 12 2025

Snow has ended across the area with subsidence in the wake of the departing clipper leading to clearing skies north of I-80 and temps dropping through the teens, while to the south mainly mid/ upper 20s where clouds remain. Poised upstream is another shortwave entering the Northern Plains. This will slide E/SE today with the brunt of the ascent (via positive vorticity advection and low level frontogenetical forcing) focused to our north across parts of MN/WI. That said a close enough brush of some weak ascent aided by an approaching front to warrant mention PoPs for light snow roughly mid morning until mid afternoon mainly north of I-80. Weak ascent and limited moisture should keep any amounts minor.

After this passes, focus will then shift toward another clipper system set to bring more accumulating snow late tonight through much of the day on Saturday. This will be on the heels of an influx of arctic air for Saturday. The energy is currently working ashore into British Columbia and will plunge SE taking on a more impressive amplitude on the western periphery of an upper low traversing near far northern Lake Superior on Saturday. This will follow a fairly similar path the our recently departed system with similar amounts generally of 1-4 inches with deep saturation in DGZ and arctic airmass to support efficient accumulations. There is also a signal for a rather narrow corridor where elevated 700-600 mb frontogenetical forcing intersects the DGZ and would be capable of higher/colder SLRs 25-30:1 possibly supportive of a ribbon or stripe of higher amounts on the order of 5-6 inches. NBM probabilities for >4" amounts are between 30-50% between Quad Cities to Burlington and increase to pockets of 60%+ across central Illinois. Have opted to issue a Winter Weather Advisory for these areas for 2-4 inch amounts, but can't rule out further adjustments to headlines and amounts as we continue to try and pin down the banding placement.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/

Issued at 337 AM CST Fri Dec 12 2025

Beyond, here comes the arctic high with at least 3 sigma cold coming down for Saturday night into Sunday morning. With the expected snow cover and cold advection from Canada, ambient lows by Sunday morning may range from 5 below to 15 below zero. Northwest sfc winds of 5-10 MPH may make for dangerous wind chills of 20 to 30 below Sunday morning, and thus the eventual need of some type of cold headline. Not quite as cold into Monday morning but still may be 20 below or colder wind chills north of I-80 which may need a headline.

Not a fan of this early blast of winter. Well, hang in there as there's light at the end of the tunnel. Long range deterministic and ensemble guidance still suggest a flattening steering flow, or a more semi-zonal west to east flow across the mid CONUS fostering an MP airmass fetch. This should lead to moderating temperatures into the 30s/40s heading into mid- week.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1115 PM CST Thu Dec 11 2025

Light snow will be near KMLI and KBRL at the start of the TAF period before tapering off. Some partial clearing and lifting of CIGs to MVFR and VFR is anticipated. Any areas that clear out with light winds could see some lower visibility restrictions in fog. On Friday, anticipate stratus and MVFR to IFR CIGs to slosh back across the region with the passage of a cold front. Flurries will be possible at all sites for a period around the frontal timing, along with a chance of light snow mainly near KDBQ by late AM/early PM that was handled with PROB30 mention. Winds will turn gusty from the W/NW with the frontal passage at 10-20+ kts. A return to VFR conditions is possible Friday evening/night before the next clipper system approaches from the west.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Winter Weather Advisory from 3 AM to 3 PM CST Saturday for IAZ063-064-076-077-087-088-098-099. Winter Weather Advisory from 6 AM to 6 PM CST Saturday for IAZ065-067-068-078-089. IL...Winter Weather Advisory from 6 AM to 6 PM CST Saturday for ILZ015-024>026-034-035. MO...None.